init

internal/og/og.go

@@ -0,0 +1,185 @@
+package og
+
+import (
+	"bytes"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/png"
+
+	"github.com/golang/freetype"
+	"github.com/golang/freetype/truetype"
+	"golang.org/x/image/font"
+	"golang.org/x/image/font/gofont/goregular"
+	"golang.org/x/image/font/gofont/gobold"
+)
+
+const (
+	imgWidth  = 1200
+	imgHeight = 630
+)
+
+var (
+	regularFont *truetype.Font
+	boldFont    *truetype.Font
+)
+
+func init() {
+	var err error
+	regularFont, err = freetype.ParseFont(goregular.TTF)
+	if err != nil {
+		panic(err)
+	}
+	boldFont, err = freetype.ParseFont(gobold.TTF)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func parseHexColor(hex string) color.RGBA {
+	if len(hex) == 0 {
+		return color.RGBA{16, 185, 129, 255} // #10b981 emerald
+	}
+	if hex[0] == '#' {
+		hex = hex[1:]
+	}
+	if len(hex) != 6 {
+		return color.RGBA{16, 185, 129, 255} // #10b981 emerald
+	}
+
+	var r, g, b uint8
+	for i, c := range hex {
+		var v uint8
+		switch {
+		case c >= '0' && c <= '9':
+			v = uint8(c - '0')
+		case c >= 'a' && c <= 'f':
+			v = uint8(c - 'a' + 10)
+		case c >= 'A' && c <= 'F':
+			v = uint8(c - 'A' + 10)
+		}
+		switch i {
+		case 0:
+			r = v << 4
+		case 1:
+			r |= v
+		case 2:
+			g = v << 4
+		case 3:
+			g |= v
+		case 4:
+			b = v << 4
+		case 5:
+			b |= v
+		}
+	}
+	return color.RGBA{r, g, b, 255}
+}
+
+func Generate(title, siteName, accentColor string) ([]byte, error) {
+	accent := parseHexColor(accentColor)
+
+	img := image.NewRGBA(image.Rect(0, 0, imgWidth, imgHeight))
+
+	for y := 0; y < imgHeight; y++ {
+		ratio := float64(y) / float64(imgHeight)
+		r := uint8(float64(accent.R) * (1 - ratio*0.3))
+		g := uint8(float64(accent.G) * (1 - ratio*0.3))
+		b := uint8(float64(accent.B) * (1 - ratio*0.3))
+		for x := 0; x < imgWidth; x++ {
+			img.Set(x, y, color.RGBA{r, g, b, 255})
+		}
+	}
+
+	c := freetype.NewContext()
+	c.SetDPI(72)
+	c.SetClip(img.Bounds())
+	c.SetDst(img)
+	c.SetSrc(image.White)
+	c.SetHinting(font.HintingFull)
+
+	titleSize := 64.0
+	if len(title) > 50 {
+		titleSize = 48.0
+	}
+	if len(title) > 80 {
+		titleSize = 40.0
+	}
+
+	c.SetFont(boldFont)
+	c.SetFontSize(titleSize)
+
+	wrapped := wrapText(title, 28)
+	y := 200
+	for _, line := range wrapped {
+		pt := freetype.Pt(80, y)
+		c.DrawString(line, pt)
+		y += int(titleSize * 1.4)
+	}
+
+	c.SetFont(regularFont)
+	c.SetFontSize(28)
+	pt := freetype.Pt(80, imgHeight-80)
+	c.DrawString(siteName, pt)
+
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func wrapText(text string, maxChars int) []string {
+	if len(text) <= maxChars {
+		return []string{text}
+	}
+
+	var lines []string
+	words := splitWords(text)
+	var current string
+
+	for _, word := range words {
+		if current == "" {
+			current = word
+		} else if len(current)+1+len(word) <= maxChars {
+			current += " " + word
+		} else {
+			lines = append(lines, current)
+			current = word
+		}
+	}
+	if current != "" {
+		lines = append(lines, current)
+	}
+
+	if len(lines) > 4 {
+		lines = lines[:4]
+		if len(lines[3]) > 3 {
+			lines[3] = lines[3][:len(lines[3])-3] + "..."
+		}
+	}
+
+	return lines
+}
+
+func splitWords(s string) []string {
+	var words []string
+	var current string
+	for _, r := range s {
+		if r == ' ' || r == '\t' || r == '\n' {
+			if current != "" {
+				words = append(words, current)
+				current = ""
+			}
+		} else {
+			current += string(r)
+		}
+	}
+	if current != "" {
+		words = append(words, current)
+	}
+	return words
+}
+
+var _ = draw.Draw